Crypto is a good alternative but will only remain as an alternative since the main money in this world will always be fiat.
There are people who believe on the possibility that crypto will replace fiat, but are we big enough to replace them or do we have the support from the government to make it happen, whether we like it or not, we are all under the control of the government.
Please notice that the acceleration of changes our world is undergoing currently is higher than ever today. I would agree with you if the world was going forward with the same pace as before, but this is not the case. Through the whole history of humankind there were no such period of time as the last 30 years when so many unpredictable things have happened. I mean the appearance of the Internet that is currently used by 3.2 billion people and the appearance of smartphones (currently used by 2.7 billion people). I bet in 10 years most of the governments will be so unlike the current ones, we can't even imagine. And there is a chance that those new governments will be preferring crypto over fiat.